The air tightness of an aluminum alloy wheel hub is an important index for measuring the performance of the aluminum alloy wheel hub. In wheel hub manufacturing enterprises, every aluminum alloy wheel hub must be inspected on the conformity with an air tightness requirement.
Common detection methods adopted include a helium gas-tightness detection method and a water air-tightness detection method. When a helium gas is adopted for detection, an inert gas of helium gas and a helium mass spectrometer need to be used. The detection equipment are expensive and the consumption of helium gas is large, leading to high overall cost. The principle for the helium gas-tightness detection is that a wheel hub needs to be placed in an air-tight space during detection; an inner cavity of the wheel hub is vacuumized; when a vacuum value is small enough, a helium gas with a certain pressure value is filled to the outer side of the wheel hub; if a leaking point exists in the wheel hub rim, molecules of the helium gas will pass through the leaking point to reach the inner cavity of the wheel hub; since the inner cavity of the wheel hub is in a vacuum environment, the molecules of the helium gas will be extracted into the helium mass spectrometer, which detects the number of helium molecules, thereby determining whether the air tightness of the wheel hub is within an acceptable range.
The principle of the water air-tightness detection is that inner and outer sides of the wheel hub are closed during detection; the wheel hub is immersed into water; then the inner cavity of the wheel hub is inflated with compressed air under certain pressure; and if an obvious leaking point exists in the wheel hub, high-pressure air in the inner cavity will form air bubbles in the water; and whether the air tightness of the wheel hub is acceptable can be further determined. Regarding the water air-tightness detection, water quality becomes worse after long-term continuous detection and needs to be changed, which consumes a large amount of clean water; in addition, a detection process needs to be observed by human eyes, which easily results in missed determination, and moreover, the detection time is long and the overall efficiency is low.
It follows that the traditional detection methods have the following defects that 1. with the helium gas, the equipment investment is large and the consumption of helium gas is high, leading to high overall cost; 2. with water air-tightness detection, a large amount of clean water needs to be consumed, with the detection time being long and the overall cost being high; therefore, the air tightness detection to the aluminum alloy wheel hub is in need of improvement.